fsync

(PHP 8 >= 8.1.0)

fsync — Synchronizes changes to the file (including meta-data)

Description

fsync(resource $stream): bool

This function synchronizes changes to the file, including its meta-data. This is similar to fflush(), but it also instructs the operating system to write to the storage media.

Parameters

stream: The file pointer must be valid, and must point to a file successfully opened by fopen() or fsockopen() (and not yet closed by fclose()).

Return Values

Returns true on success or false on failure.

Examples

Example #1 fsync() example

<?php

$file = 'test.txt';

$stream = fopen($file, 'w');
fwrite($stream, 'test data');
fwrite($stream, "\r\n");
fwrite($stream, 'additional data');

fsync($stream);
fclose($stream);
?>

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User Contributed Notes 1 note

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Dave Gebler ¶

3 years ago

Two points worth noting:

1. fsync() is not suitable for high throughput, use it only when the durability of a file write really matters to you.

2. fsync() includes an implicit call to fflush() so you don't need to manually flush before you sync.